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Evidence of altitudinal increase in photosynthetic capacity : gas exchange measurements at ambient and constant CO2 partial pressures / Caroline C Bresson in Annals of Forest Science, 66 (2009) 

Public Citation [article]  inAnnals of Forest Science > 66 (2009) . - 8 p. Titre : Evidence of altitudinal increase in photosynthetic capacity : gas exchange measurements at ambient and constant CO2 partial pressures Type de document : Électronique Auteurs : Caroline C Bresson ; AndrewS Kowalski ; Antoine Kremer (1951-) ; Sylvain Delzon (1977-) Année de publication : 2009 Article en page(s) : 8 p. Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Assimilation nette, photosynthèse, métabolisme du carbone, photorespiration, respiration, fermentation (anoxie,hypoxie) [CBNPMP-Thématique] CO2 Résumé : Because all microclimatic variables change with elevation, it is difficult to compare plant performance and especially photosynthetic capacity at different elevations. Indeed, most previous studies investigated photosynthetic capacity of low- and high-elevation plants using constant temperature, humidity and light but varying CO2 partial pressures (P CO 2). Using gas exchange measurements, we compared here maximum assimilation rates (A max) at ambient and constant-low-elevation P CO 2for two temperate tree species along an altitudinal gradient (100 to 1600 m) in the Pyrénées mountains. Significant differences in A max were observed between the CO2 partial pressure treatments for elevations above 600 m, the between-treatment differences increasing with elevation up to 4 μmol m−2 s−1. We found an increase in A max with increasing elevation at constant-low-elevation P CO 2 but not at ambient P CO 2 for both species. Given a 10% change in P CO 2, a proportionally higher shift in maximum assimilation rate was found for both species. Our results showed that high elevation populations had higher photosynthetic capacity and therefore demonstrated that trees coped with extreme environmental conditions by a combination of adaptation (genetic evolution) and of acclimation. Our study also highlighted the importance of using constant CO2 partial pressure to assess plant adaptation at different elevations. Lien pérenne : DOI : 10.1051/forest/2009027 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=143282 Bresson, Caroline C, Kowalski, AndrewS, Kremer, Antoine (1951-), Delzon, Sylvain (1977-) 2009 Evidence of altitudinal increase in photosynthetic capacity : gas exchange measurements at ambient and constant CO2 partial pressures. Annals of Forest Science, 66: 8 p..

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